Soft-face hammer



June 26, 1962 R. F. WEST ET AL 3,040,792

SOFT-FACE HAMMER Filed Aug. 51, 1960 FIG. I

FIG. 2

INVENTORS ROBERT E WEST By WALTER ROB/NSON WWCQ ATTO EYS United StatesPatent 3,040,792 SOFT-FACE HAMMER Robert F. West, Simsbury, and WalterH. Robinson, West Hartford, Comm, assignors to The Stanley Works, NewBritain, Conn., a corporation of Connecticut Filed. Aug.'31, 1960, Ser.No. 53,087 7 Claims. (Cl. 145-36) The present invention relates tohammers of the type having relatively soft striking faces, generallyknown as soft-face hammers.

Hammers having striking tips or faces of yieldable or deformablematerial are used when it is desired to avoid inarring the surface of anarticle being struck. These tools employ a striking surface formed of amaterial softer than that being struck, and various materials, includingplastics, leathers, soft metals, etc., have been proposed and utilizedfor this purpose. In order to obtain maximum efficiency in operation, itis desirable to be able to change the materials used for the strikingtip so as to obtain a striking surface which is somewhat softer than thesurface to be struck, but which is not unduly so.

It is an object of the present invention to provide a novel hammerstructure having striking tips of relatively soft deformable materialwhich are readily interchangeable, ruggedly mounted and free fromtendency to loosen during use.

- Another object is to provide such a hammer having readily removableand interchangeable mounting sockets for firmly holding and supportingstriking tips of resiliently deformable material without looseningduring use.

It is also an object to provide such a hammer which is ruggedlyconstructed and wherein the handle is secured inthe head in a novelmanner to prevent any twisting or looseness therebetween.

-A further object is to provide such a hammer having reversible strikingtips so that either transverse face may be used and to provideresiliently deformable striking tips of a novel and superior design asto enable extended usage and ready reversibility and interchangeability.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereafter set forth and the scope of theapplication which will be indicated in the appended claims.

In the drawings:

'FIG. 1 is an exploded perspective view of a hammer embodying thepresent invention with a portion of one tip mounting socket broken awayto show internal structure;

FIG; 2 is an enlarged side elevational view of the assembled hammer inpartial section to show internal structure; and

FIG. 3 is a sectional view along the line 3--3 of FIG. 2.

Referring to the drawings, a soft-face hammer embodying the presentinvention has a rigid metallic head 2 having a body portion 4 ofgenerally cylindrical configuration with a handle mounting aperture 6extending radially through the center thereof. Projecting outwardly fromeither end of the body portion 4 are threaded bosses 8, each of whichhas an eccentrically located recess 12 in its outer surface for apurpose to be described more fully hereinafter.

Engaged on each of the bosses 8 is a tubular tip mounting sleeve orsocket 14 providing a generally cylindrical "ice ture extending throughthe socket. Intermediate the length of the tip receiving aperture 16,and preferably more closely adjacent the outer end thereof, is acircumferential internal rib 22 providing an abutment of reducedcross-section in the tip receiving aperture. Also, spaced about theinner surface of the socket are a plurality of short longitudinalgrooves 24 which preferably extend into or through the internal rib 22,both for a purpose to be described fully hereinafter. To facilitategripping and rotation of the sockets, the outer periphery is knurled orroughened as indicated by the numeral 25.

Securely mounted in the tip mounting aperture 16 of the socket 14 is asymmetrical striking tip 26 of deformable material dimensioned andconfigured to closely conform to the periphery of the mounting aperture16 and having inner and outer transverse striking surfaces 27. Uponinsertion of the striking tip 2-6 into the socket, the internal rib 22.deforms the tip and causes the tip material to lock behind it andprevent looseness during use. Some of the tip material extends into thelongitudinal grooves 24 so as to form locking keys for the tip in theaperture 16 and eliminate any tendency for relative rotation of the tipin the socket aperture.

With resiliently deformable materials such as plastics, the tip 26 ismerely forced into the socket 14 and the resiliently compressed materialexpands as it moves past the internal rib 22 until the inner face 27 ofthe tip bottoms in the aperture against the collar portion 1 8. Some ofthe tip material is'also forced into the longitudinal grooves 24 duringthe compression attendant to passage through the rib 22. This internalholding arrangement in the socket insures firm and constant retentionof. the tip with substantial freedom from any tendency toward loosenessor rotation.

As will be readily apparent from the drawing, the close contact of theperipheral wall of the socket 14 with the peripheral surface of the tip26 provides a reinforcement and lateral support and prevents excessiveradial deformation as well as providing a path for the transmission ofshock and stress into the body portion of the head where the forces canbe more readily dissipated, thus materially extending the life of thetip. Preferably the tip receiving aperture is on the order of one-halfthe length of the tip to as to provide optimum characteristics ofsupport.

Upon being subjected to the percussive forces during initial use, someof the plastic material of the inner face 27 of the striking tip 26 willbe extruded or forced into the eccentrically located recess 12 in theboss surface 10 to provide a self-forming dowel pin 28 which elfectivelyprevents inadvertent loosening of the threaded connection between bossand mounting socket during use. However, to disconnect the members, itis only necessary to apply suflicient rotational pressure to shear orbreak the dowel pin 28.

Although any relatively soft and deformable material may be used for thestriking tips of the present invention, it is preferable to employresiliently deformable materials having the desired degree of hardnesssince permanent deformation of the striking face or the body of the tipis thereby avoided. Such materials are particularly desirable since thetip is desirably reversible in accordance with the preferred embodiment.Exemplary of such resiliently deformable materials are natural rubbersand various synthetic plastics such as nylon, synthetic rubbers, andcellulose esters.

The preferred configuration for the striking tip is illustrated in thedrawings and is one which has proven to be highly superior in extendedtesting. As illustrated, the tip is symmetrical and generallycylindrical, with a cylindrical body and convexly curvilinear strikingfaces 27 at both ends. Both striking faces 27 are similarly determinedby two radii, a large radius being used for the striking surface whichcomprises the major portion of the face and a small radius along theperiphery of the striking surface to blend smoothly from the largeradius into the side of the Striking tip. The length of the tip is mostdesirably on the order of the width of the tip, and preferably somewhatless. This configuration has proven particularly advantageous inabsorbing and dis-. tributing the shock and stress throughout the bodyof the tip and to the head of the hammer through the contact with thesides of the socket and through the inner curvilinear surface whichbutts against the boss 8. The convexly curvilinear configuration of thestriking face disposed inwardly of the socket ensures direct contactbetween the crest of the tip and the center or boss of the hammer headso that the major transmission of impact forces occurs in this area.This construction avoids major transfer of impact force at a pointoffset from the center of the two elements and the attendant increase instresses, and has been found to provide a highly effective, long-livedsoft-face hammer.

-As a specific example of a tip construction which has proven highlyadvantageous, a cylindrical tip is formed with an axial length of 1inches and a diameter of l.341.38 inches depending upon thedurometerrange is desired, the diameter decreasing with increase inhardmess. The major transverse surface is determined by a radius of /2inches and the blending radius is $4 inch.

Thus, the tip mounting sockets containing tips of various hardness maybe readily interchanged in accordance with the needs of the work. Whenone striking surface of the tip becomes worn, the tip itself may bereversed in the socket by unthreading the rocket from the boss andexpelling the tip from the socket by means of the tool inserted throughthe threaded aperture 20 in the collar 18, after which the tip isreversed and driven back into the socket apertureld so as to expose theunworn str k f Ih e handle 36 is securely mounted in the eye 6 of thehead so as to prevent any twisting or looseness therebetween by means ofseveral features. As shown in FIGS. 2. and 3, the mounting eye oraperture 6 tapers inwardly from both ends to provide a portion ofreduced crossscti n nterme iate n length and a plurality of Shortlongitudinal grooves 38 are broached into the head about the peripheryof the eye at this portion of reduced cross section so that when'thehandle 36 is driven into the eye 6, some of the wood enters into thegrooves 38 and locks the handle from rotation therein. A wedge 49 isdriven into the terminal end of the handle to deform and eX- pand theterminal portion of the handle into engagement with the periphery of theeye 6 above the portion of reduced c ssn- AS. Will be readilyappreciated, the weight of the hammer can be varied by selection of thedimensions and material used for the head of the hammer and to somedegree by the material and dimensions for the sockets. Because of thestresses and shock encountered during use of the hammer, the head andsockets are preferably fabricated from metal to provide optimumdurability. When using hammers of heavier weight, the tips utilizedtherein are preferably increased dimensionally in proportion.

As will be apparent to persons skilled in the art, various modificationsand adaptations of the structure above described will become readilyapparent without departure from the spirit and scope of the invention,the scope of which is defined in the appended claims.

We claim:

1. In a soft-face hammer, the combination comprising a head having ahandle receiving aperture therein and tubular rigid sleeves at its endseach providing tip mountingapertlil' s, Said tubular sleeves each havingan internal portion intermediate the length of said aperture projectinginwardly thereof to define an aperture of lesser crosssection than thatof the outer end thereof, the surfaces of said internal portionextending longitudinally of said sleeve being inclined to provide rampsurfaces; and symmetrically configured striking tips of deformablematerial removably seated in each of said tip mounting apertures, saidtips extending outwardly of said tip mounting apertures and having theside surfaces in close-fitting engagement with the side surfaces of thetip. mounting apertures, said tips having end surfaces of convex-1ycurvilinear configuration with the crest of the inner end surface seatedfirmly against said hammer head, said sleeve internal portion beingembedded in and deforming the tip material to firmly lock the tip intosaid tip mounting aperture against inadvertent release, said inclinedrampsurfaces providing gradual compression of the tip material forlongitudinal movement of the tip relative to said sleeve internalportion, said'tips being releasable from said sleeve internal portionsand reversible in said sleeves to provide a pair of striking surfaceseach of convexly curvilinear configuration.

2. A hammer in accordance with claim 1 wherein said tip receivingapertures of the tubular sleeves are cylindrical in configuration andsaid tips are fabricated from a resil, iently deformable syntheticplastic material and are of generally cylindrical configuration withsaid convexly curvilinear striking surfaces beingdetermined by tworadii, a large radius providing a smooth curve over substantially theentire striking surface and a relatively small radius smoothly blendingfrom said large radius into the side of the tip.

3. In a hammer having striking faces of resiliently deformable material,the combination comprising a metallic head having tubular sleeves ateach end providing tip mounting apertures with an internal ribintermediate the length thereof and longitudinal grooves in said rib;and striking tips of resiliently deformable material removably seated ineach of said apertures in close-fitting engagement with the periphery ofthe tip mounting aperture, said internal rib being embedded in anddeforming the tip material to firmly lock the tip into said tip mountingaperture against inadvertent release, portions of said tip materialextending into said longitudinal grooves to prevent rotation in said tipmounting aperture.

4. A hammer having striking faces of resiliently deformable materialcomprising a cylindrical metallic head having a handle receivingaperture in the center thereof and threaded bosses projecting outwardlyfrom the ends thereof; a handle having an end portion securely engagedin said handle receiving aperture; a pair of cylindrical tubular tipmounting sockets each providing a tip mount ing aperture extendinginwardly from one end thereof and a collar at the other end thereof witha threaded aperture therein threadably engaged upon said bosses, each ofsaid tubular sockets having an internal circular rib projecting radiallyinwardly of said tip receiving aperture intermediate the length thereofand a plurality of longitudinal grooves in said rib; and generallycylindrical striking tips of resiliently deformable material removablyseated in each of said tip mounting apertures, each of said tips havingits peripheral surface in close fitting frictional engagernent with theperipheral surface of the tip mounting aperture and said internal rib ofthe socket being embedded in and deforming the tip to firmly lock saidtip in the socket against inadvertent release, and portions of said tipextending into said longitudinal grooves to prevent twisting movement.

5. A hammer in accordance with claim 4 wherein said striking tips aresymmetrical and reversible in said sockets, said tips having curvilinearstriking faces determined by two radii, a large radius providing asmooth curve over substantially the entire striking face and arelatively small radius smoothly blending from said large radius intothe side of the tip. V

6. A hammer having striking faces of deformable material comprising ametallic head of generally cylindrical configuration having a handlereceiving aperture extending therethrough normal to its axis and havingthreaded bosses extending outwardly from its ends, each of said bosseshaving an eccentrically located recess in the outer surface thereof; ahandle having an end portion secured in said aperture; a pair ofgenerally cylindrical tubular tip mounting sockets each providing agenerally cylindrical tip receiving aperture extending inwardly from oneend thereof and a collar portion at the other end thereof with athreaded aperture engaged on said threaded bosses, each of said tubularsockets having an internal circular rib projecting inwardly of said tipreceiving aperture intermediate the length thereof and havinglongitudinal grooves spaced about the inner periphery thereof extendingthrough said internal rib; and generally cylindrical striking tips ofresiliently deformable material seated in said tip receiving aperturesin close fitting engagement with the periphery of the apertures, saidtips being symmetrically configured and having curvilinear strikingfaces defined by two radii, said internal rib extending into anddeforming the resilient material of the tip to firmly =lock said tip insaid socket against inadvertent release and portions of the tipextending into said longitudinal grooves to prevent rotation of the tipin the socket, the inner face of each of said tips having a portionextending into said eccentrically located recess in the face of the bossto lock said socket against inadvertent rotation on said boss.

7. A hammer having striking faces of resiliently deformable materialcomprising a metallic head of generally cylindrical configuration havinga handle receiving aperture extending therethrough normal to its axisand having threaded bosses extending outwardly from its ends, each ofsaid bosses having an eccentrically located recess in the outer surfacethereof, said handle receiving aperture being of generally circularcross-section and tapering from exit and entrance ends to anintermediate portion of reduced cross-section and having longitudinal-1y extending grooves spaced about its periphery in said portion ofreduced cross-section; a handle having an end portion secured in saidaperture with portions extending into said longitudinally extendinggrooves to prevent twisting movement thereof in said head; a wedge insaid handle end portion at the exit end of said aperture forcing saidhandle into tight engagement with the tapering side walls of the exitend of the handle receiving aperture; a pair of generally cylindricaltubular tip mounting sockets each providing a generally cylindrical tipreceiving aperture extending inwardly from one end thereof and a collarportion at the other end thereof with a threaded aperture engaged onsaid threaded bosses, each of said tubular sockets having an internalcircular rib projecting inwardly of said tip receiving apertureintermediate the length thereof and having longitudinal grooves spacedabout the inner periphery extending through said internal rib; andgenerally cylindrical reversible striking tips of resiliently deformablematerial seated in said tip receiving apertures in close fittingengagement with the periphery of the aperture, said tips bein'gsymmetrically configured and having curvilinear striking faces definedby two radii, said internal rib extending into and deforming theresilient material of the tip to firmly lock said tip in said socketagainst inadvertent release and portions of the tip extending into saidlongitudinal grooves to prevent rotation of the tip in the socket, theinner face of each of said tips having a portion extending into saideccentrically located recess in the face of the boss to lock said socketagainst inadvertent rotation on said boss.

References Cited in the file of this patent UNITED STATES PATENTS460,115 Colton Sept. 29, 1891 2,518,059 Pemmerl Aug. 8, 1950 2,525,429Seip Oct. 10, 1950 FOREIGN PATENTS 5,648 Great Britain 1911 607,896Great Britain Sept. 7, 1948 23,061 Australia Jan. 7, 1936 776,284 GreatBritain June 5; 1957

